Useful Searches

Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

Plow randomly falls

I had the pump fluid, filter and canister changed at the end of last year, this is when the problem started, when the plow is lifted up it will randomly fall to the ground, but not all the time. I was told by the repair company that the plug is the issue. im determined its the pump. any help is appreciated. its a 9' pro plus ultramount.

I wouldn't think it is the pump. The pump only creates hydraulic pressure to raise/angle the pump. If it is dropping, then something is causing a release of pressure. The pump only operates when the motor is running, and the motor doesn't run when you are lowering the plow.

That is about all the knowledge I can impart on this topic, hope it makes sense, and someone else can help more than me.

Yeah, I would say it is in the plug or harness. So, while you are driving the solenoid probably thinks it should open and relieve pressure because it is loses connection caused by faulty harness or plug.

That's typically the cause of the condition being described. The "seat" in the valve has likely softened which prevents it from holding the fluid in place. When the fluid is allowed to bypass, the plow can drop.

I find it's the controller (hand helds especially) or the harness/grill plug 100% of the time. Since the Insta-act's inception I've not once seen the valve cause an instant drop. Only a slow leakdown, thus the reason I asked which it's suffering from.

Easy way to test for a faulty controller is to raise the plow and then disconnect the controller.

When you raise the plow and then release the button the plow should stay up. If you disconnect the controller you wll eliminate or verify the controller as the problem. If the plow doesn't drop with the controller out of the system you probably need a controller but if it still drops the controller is OK, look further. You could also take the valve cover off and disconnect one of the wires from the S1 valve coil. (Top right coil on an isarmatic) This will narrow the problem down to electrical or hydraulic. If the plow drops even with one of the wires off then you have a failing check valve in S1 and need a new valve cartraige (not likely in my opinion because check valve don't randomely open, they just don't close causing immediate leak down / drop)

I suspect you have some sort of short curcuit that is causing power to be applied to the white / yellow wire that goes to the S1 valve. All three coils have a common ground so it has to be on the white / yellow positive wire somewhere between the coil on the plow and the controller. Check all the pins at the grill plug and the control harness right up to the controller. I suspect the controller is failing if it is old.

If you don't have an isarmatic then give us the plow model and we can give you wire colors that apply.